For those wiring on board chargers, does wiring on the battery side of your contactor make a difference? I had last build that way, but I am not sure I want to have to have the contactor closed for charging? Charger and bms will be in charge of cutting things off if it gets fishy, but I might be forgetting something obvious.

thx!

Wire the charger directly to the battery, not through the contactor. It's actually better if the charger isn't connected to the controller when charging. If you want an extra safety let the BMS cut off power to the charger with a relay on the AC input.